In a relay satellite mounted with a digital channelizer that relays data from a plurality of beams to a plurality of beams, relaying data in wideband signals from each of the beams can be performed by increasing sampling speeds of the AD (Analog to Digital) converter (A/D), the DA (Digital to Analog) converter (D/A), and the digital-signal processing unit. A technology concerning such a relay satellite provided with a digital channelizer is disclosed in Patent Literature 1 described below.